Ecorse Creek Improvements and CSO Program
LOCATION: Dearborn, Michigan
CLIENT: Wayne County, Michigan
PROJECT DESCRIPTION
CTI performed remediation and restoration of contaminated sediments and soils of the off-site areas of the Imperial Oil / Champion Chemical Superfund Site Operable Unit 1 (OU-01). The project was managed locally by the USACE NY District for U.S. EPA Region 2, the overall client. Industrial chemical processing and oil reclamation were previously performed on adjacent properties from 1912 to 2007. These industrial activities resulted in contamination of soils and sediment in neighboring areas, including residential properties, Birch Swamp Brook and adjacent floodplains. The project site was added to the EPA National Priority List of Superfund Sites in 1982, and divided into 3 Operable Units. Various remediation efforts were performed across the site beginning in 1998. In 2012, a Focused-Ecological Risk Assessment was performed for Birch Swamp Brook and surrounding woodlands. Sample results indicated that PCB concentrations were found above 2.13 milligrams per kilogram (mg/kg), the selected cleanup number for PCBs in soil.
CTI’s remediation effort was associated with these areas in OU-01. CTI remediation efforts included surgical excavation and disposal of over 3,735 CY of PCB-contaminated soil along 800 feet of Birch Swamp Brook and 1.5 acres of adjacent wetland areas. Approximately 350 CY of PCB-contaminated soils were characterized as TSCA waste, and were disposed of accordingly. Prior to mobilization, extensive permitting and plan preparation was required to satisfy the requirements of all stakeholders. CTI was tasked with performing remediation with minimal disturbance and impact to the existing site. The project site was heavily wooded and required selective clearing along proposed haul roads and tree removal along Birch Swamp Brook and floodplain excavation areas. Timber swamp mats were staged along the haul road within wetland areas. Prior to excavation of Birch Swamp Brook, a well point system was installed to dewater and facilitate dry excavation conditions along the approximately 800’ area. At the completion of excavation to predetermined contract limits and various over-excavation areas, confirmatory sampling was performed to verify only PCB concentrations below 2.13 mg/kg remained. Contaminated soil was temporarily stockpiled in a poly sheeting-lined enclosure area within the Site Staging Area prior to T&D. Wetland and upland areas were backfilled with NJ clean topsoil material and restored in accordance with NJDEP permit requirements. Winter weather conditions caused various delays in field work, presented safety challenges, and resulted in delayed restoration activities which were performed during a Spring 2017 remobilization.
To ensure the safety of site personnel and surrounding properties, a personal and perimeter air monitoring program was implemented. Exclusion, Contaminant Reduction, and Support Zones were established, and equipment and personnel were decontaminated to mitigate the risk of PCB-contaminated soils traveling off site. CTI’s operating engineers, laborers and site management successfully completed remediation and restoration; performing over 7,000 labor hours with no OSHA recordable injuries.